The invention relates to a device for centering preformed components for the flat implantation thereof by means of an automatic setting machine.
For the construction of high frequency electronic circuits in particular, the technique called flat implantation of the components is more and more widely used. This technique consists in providing the electric contact of the component on the side of the printed circuit where its body is situated, that is to say in placing the body of the component and the connections on the side of the printed circuit where the conducting strips are situated. Contrary to the technique in which the printed circuit is pierced with holes for passing pins or lugs of the component therethrough and in which the body is placed on the side opposite that where the connections are provided, this technique reduces the parasite signals due to the radiation from the ends of the pins or lugs when the electronic circuit is operating.
Furthermore, the construction of circuits is automated more and more but the machines known up to now do not allow flat implantation of all the types of components. In fact, some components such as integrated circuits have been specially provided for flat implantation and, in a standard mode, these components have a chip package substantially in the form of a right angled parallelepiped with square or rectangular base. On the surface of the side of the chip carrier intended to face the circuit, that is to say the bottom of the chip carrier, flush conducting elements are provided ensuring the contact between the active part of the component and the printed circuit. Fixing to the printed circuit is either achieved by means of a conducting adhesive and, in this case, it is the contacts which are coated with adhesive, or through the chip carrier itself with a more conventional adhesive.
Other components intended to be implanted in the flat condition are also formed with a chip carrier, but the connection means are pins or lugs which project from at least one of the sides other than the top or bottom of the chip carrier. These pins or these lugs are preformed so that their free end is in the plane of the bottom of the chip carrier so that, when the bottom is on the printed circuit, the free end of each pin or lug may be in contact with a conducting strip of the printed circuit.
Thus diodes, transistors or other types of components are formed together with a chip carrier substantially in the form of a right angled parallelepiped.
For automatic implantation, an arm takes the components one by one and places them at given positions.
So that the positioning is correct, the components must be correctly positioned with respect to the arm, which means that before being picked up by the arm they must be accurately centered. Such centering is achieved by means of a device forming part of the insertion chain which is sometimes mounted for rotation so as to orient the component in a given way with respect to the manipulating arm so that the kinematics of this latter is the simplest possible.
The components are placed on the circuit by means of another manipulating arm, or any other device, which takes them from a supply magazine having compartments in which the components are placed one by one. The support is for example in the form of a strip and the components are taken from the compartments by a suction member associated with said other manipulating arm.
It is the centering phase which presents disadvantages and raises problems, to overcome which is the purpose of the present invention.
In fact, centering of standard type components takes place on a plate, possibly rotatable for correct orientation with respect to the implantation arm. The plate is provided with two pairs of jaws perpendicular to each other for clamping the sides, other than the bottom and the top of the chip carrier two by two. The jaws of each pair clamping two opposite sides move together and a the same speed relatively to one another. Consequently, when the four jaws are clamped, the component is centered.
Such a device cannot be used for centering preformed components for it means that the jaws clamp the lateral lugs or pins, which causes deformation thereof. Consequently, if this same supply magazine contains components of the two types, two different machines or two different methods must be provided for centering.